calpain and Infertility--Male

In a model of male sterility (MTp53) owing to enforced p53 expression in spermatocytes II and spermatids of transgenic mice, we focused on the role of caspases. Most of them are expressed in all differentiation stages, but only the transcriptional levels of caspase-2 and caspase-3 are modified in MTp53 germ cells. In normal testis, cleaved caspase-3 and caspase-9 are detected during the elongation of spermatids. Despite this constitutive presence of caspases during terminal differentiation, calpains are the main effectors of germ cell loss in MTp53 testes: calpain 1 RNA levels are increased, caspase-3-like activity is markedly decreased while calpain activity is higher and the calpain inhibitor E64d ((2S, 3S)-trans-epoxysuccinyl-L-leucylamido-3-methylbutane ethyl ester) reduces TUNEL labeling in MTp53 testis, whereas pancaspase inhibitor zVADfmk (N-benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethylketone) has no effect. Our work suggests that despite the presence, and potent involvement, of caspases in male haploid cell maturation, calpains are the executioners of the death of terminally differentiating germ cells.

Topics: Amino Acid Sequence; Animals; Calpain; Caspase 2; Caspase 3; Caspase 9; Caspases; Cell Death; Enzyme Activation; Gene Expression; Gene Expression Regulation, Enzymologic; Infertility, Male; Male; Meiosis; Mice; Mice, Transgenic; Molecular Sequence Data; RNA, Messenger; Sequence Alignment; Spermatids; Spermatocytes; Spermatogenesis; Testis; Tumor Suppressor Protein p53

The dynamics of calpain and involvement of apoptosis in sperm formation disorder of the unaffected testis in rats with experimental testicular torsion were investigated.. Using 6-week-old Wistar rats, an experimental unilateral testicular torsion model was prepared. The bilateral testes were excised 1, 3, 5, 7, 14, 35, and 70 days after the left testis was twisted, and the unaffected testes were subjected to immunohistological staining, sodium dodecyl sulfate polyacrilamide gel electrophoresis and Western blotting using anti-calpain antibodies. Apoptosis was detected by the TdT-mediated dUTP biotin nick end-labeling (TUNEL) method.. By immunohistological staining, positive immunostaining by anti-pro mu-calpain antibody was observed in the spermatocyte nucleus, but not with anti-pro m-calpain antibody. The staining was increased until 7 days after testicular torsion, then decreased with progression of sperm formation disorder. By Western blotting, the intensity of staining with anti-pro mu-calpain antibody was increased until 7 days after torsion of the testis. Apoptosis expression in the unaffected testis was significantly inhibited by addition of a calpain inhibitor.. It was suggested that mu-calpain may be involved in apoptosis expression in sperm formation disorder of the unaffected testis in unilateral testicular torsion.

Topics: Animals; Apoptosis; Blotting, Western; Calpain; Immunohistochemistry; Infertility, Male; Male; Rats; Rats, Wistar; Seminiferous Tubules; Spermatic Cord Torsion; Spermatogenesis